Discussion
Medicinal plant diversity used for ethnoveterinary in Suro Barguda District
The reported ethnoveterinary medicinal plants of Suro Barguda District showed that the study area is relatively rich in ethnoveterinary medicinal plant diversity and indigenous knowledge related to each traditionally used species (Appendix 1). Comparatively a high diversity of ethnoveterinary medicinal plant species was recorded than in other cultural communities of Ethiopia [34, 35, 36]. All the documented ethnoveterinary plant species were harvested from the wild. This finding was in agreement with the reports of [37] in which 95.7% of the medicinal plants were collected from the wild. Overgrazing, deforestation, charcoal making, and firewood collection were claimed as major factors affecting the ethnoveterinary plant species of the study area.
Specification of livestock ailments, number, and part of plant species used
Even though livestock traditional medicinal plants of the district were asserted to be applied for ailments affecting chicken, sheep/goats, cattle, equines, or camels the majority of the reported medicinal plant species were found to be applied to treat one or more of the sixty-two different cattle ailments (Appendix 1). Eighteen (39%) equal medicinal plant species were mentioned to be used specifically against twenty-one ailments of goats/sheep and nineteen ailments of equines respectively.
The majority of ethnoveterinary medications were reported to comprise medicinal parts of a single medicinal plant. This finding was in line with the reports of [35, 37, 38, 39, 40]. The remaining was prepared using formulations from two or more species. [34] also reported that healers used multiple plants in the mixture to increase the strength and efficacy of the drug. Amongst all plants reported, the highest proportion of species was claimed to treat breathing problems followed by diarrhea. The highest number of multiple ethnoveterinary uses was recorded for Croton macrostachyus and Teclea salicifolia (each used against six ailment types) while Calpurnia aurea was used to treat five livestock diseases (Appendix 1).
Similar to some other previous findings such as [34, 37, 39, 40] leaves were the most widely used plant parts for ethnoveterinary medicine preparations followed by barks and roots in the study area (Figure 4). On the other hand, other findings for instance [36, 41, 42,] reported different results which showed that roots were the most frequently utilized plant parts in their respective research areas. The possible reason could be that people living in different ecological zones could use different plants and plant parts in their treatment system. The majority (97.8%) of remedies were prepared from freshly harvested plant parts. This finding was in line with the reports of [36, 39, 40, 42, 43, 44, 45], whereas 2.2% were prepared from dried forms. As reported by informants, from their long experience high efficacy was attained from freshly collected plant parts since they contain many bio-active ingredients in the form of secondary metabolites.
Viscum congolense, Clematis simensis, and Lannea rivae were the most preferred ethnoveterinary medicinal plants to treat breathing system diseases which were the most prevalent animal health problems reported in the study area (Table 2).
Livestock ailments, remedy preparation, routes of administration and dosages
Most of the veterinary ailments belong to the breathing system disease category followed by gastrointestinal diseases. Breathing problems and diarrhea were known to be the most commonly described forms of veterinary ailments in the district. This result corroborates with the report of [40]. Healers treat veterinary ailments based on observation of the animals or evidence obtained by asking the livestock owners about major symptoms shown by the diseased animals and medicines were commonly given only after the diseased animal was visually examined by a traditional healer for any symptom on its suspected body part.
Diverse modes of ethnoveterinary remedy preparations were mentioned to be used in the district based on the type and degree of complexity of livestock ailment. Chopping/pounding the remedial part and making its solution with cold water was found to be the major method of local remedy preparation (Figure 5). This finding was in agreement with the reports of many studies such as [44, 45, 46]. Oral administration of traditional medicines was reported as the main route in the treatment method of most diseases. This finding was in line with the reports of [8, 36, 37, 42, 44, 46]. This was followed by nasal administration. Rubbing or pasting herbal preparations were also commonly reported treatment methods for handling dermatological diseases. The physical appearance of the diseased animal and visually confirmed the degree of complexity of illness was used to determine doses of traditional medicines in treating livestock ailments. Some traditional practitioners reported the use of the coffee cup, water glasses, and bottles to determine dosage for some traditional medicines, while others reported using their fingertip or full of a small dish unprocessed parts to treat ailments. However, no standardized doses of herbal preparations were reported by traditional healers for any of the preparations used to treat livestock ailments in Suro Barguda District even if they used such various units of measurements. Similar findings have been reported in other studies in Ethiopia such as [18, 44, 47, 48, 49].
Since informant consensus is used to identify the most cited plant species for its particular importance the highest plant use citation was recorded in the present study for breathing system diseases with the highest ICF value (Table 5). Viscum congolense was highly effective in treating breathing system diseases, whereas Cyphostemma serpens was identified as having the highest healing potential in treating blackleg, hepatitis, and FMD (Foot and Mouth Diseases) with FL tests (Table 6). Informant consensus factor values (ICF values) were used to identify the harmony of the informants on the reported cure for the group of ailments (breathing system diseases) of the plant while fidelity level (FL) computes the significance of a species (Viscum congolense) to treat a given disease (breathing system diseases). Hence, their analysis values were confirmed as the information obtained was tangible.
Use diversity of ethno veterinary medicinal plants
With direct matrix ranking exercise made among five ethnoveterinary medicinal plant species to identify those having multipurpose, Prunus africana was ranked first (most - threatened) followed by Syzygium guineense var. guineense and Combretum collinum. Higher direct matrix ranking values indicated that the plants have been used for different purposes and vice versa. The output indicated that these multipurpose medicinal plant species were exploited more for firewood, charcoal, and construction purposes than for their medicinal uses.
All ethnoveterinary medicinal plant species in the district were cited for one or more uses other than their medicinal role such as used for environmental services, construction and material making, fodder, and live fences, fuelwood (charcoal and firewood), as wild food or poison (Figure 6). Out of the 46 different medicinal plant species used for livestock ailments treatment, the highest medicinal use values (UVmed) were recorded for Lannea rivae followed by Dichrostachys cinerea (Table 7).
Water served as ‘solvent’ almost in all ethno formulations of traditional medicines whenever dilution is required. Different additives were incorporated in 23.4% of the whole ethno formulations. Informants reported that certain additives were frequently used to improve the suitability of some remedies that were taken orally either through reducing their bitterness and bad flavor or increasing their efficacy. The highest usage of additive was reported for “Magado” salt (locally produced salt).
Distribution of indigenous knowledge on medicinal plants among different social groups in the community of the study area
Though more medicinal plants were reported by men than women, the difference was not significant (P >0.05) when the average number of medicinal plants mentioned by each group was compared. This could be because both men and women were knowledgeable on the use of traditional plant remedies regardless of the relative dominance of medicinal plant tradition by men which could be related to the transfer of traditional knowledge along the male line in the study area. Similar results were reported by [43, 50]. Furthermore, [51] reported as there was relatively equivalent medicinal plant knowledge among men and women traditional medicine practitioners among three communities in northeastern Brazil, and [52] reported similar information for a community in southwest Niger. There was no significant difference observed in the number of medicinal plants listed by informants living around health centers and those living relatively far away from these health centers. However, there was a significant difference (P = 0.00) in the number of medicinal plants reported by senior members of the community (> 39 years old) and young- to middle-aged members (< 40 years old) - more number of medicinal plants was reported by elders than by youngsters. This could be due to their high degree of opportunity for more cultural contact and experience with plants and associated therapeutic uses than that of younger people or due to the absence of sharing indigenous knowledge freely because of its secrecy and if it presents being along the preferred male line of the family of the ethnic group of the study area. Similar reports were made by [34, 44, 50, 53, 54, 55, 56]. Similarly, significant differences were also seen in the number of medicinal plants reported by key informants and randomly taken informants, illiterate and literate informants. More medicinal plants were reported by illiterates and key informants than literates and randomly taken informants (Table 8). This could again be related to the impact of lifelong experience and serious secrecy in using medicinal plants in the former, and modernization in the latter case. Similar results were reported by [54, 55].
A large number and types of livestock diseases (79 disease types) for which diseased livestock was visited by traditional healers indicated a preference of local people in the study area to use traditional medicines than modern medication. The reported reasons for this to happen were efficacy and availability of these medicines, cultural trend, and life standard (being poor), factors which force the community to visit traditional healthcare practitioners than modern healthcare centers with unreasonable prices. Similar findings were reported by [42, 44].
Indigenous knowledge transfer
Using wild plants for medicine traditionally is an indigenous science. Indigenous knowledge systems are the multifaceted assortments of knowledge, know-how, practices, and representations that guide human societies in their numerous interactions with the natural environment such as agriculture and animal husbandry; struggles against disease and injury; and strategies for coping with changing environments. It is through this day-to-day and the inevitable interplay between people and surroundings that indigenous knowledge systems have developed miscellaneous structures and content; complication, flexibility, and practicality; and distinctive patterns of interpretation anchored in specific worldviews [57].
Knowledge is produced and transferred through communications within specific social and agroecological contexts. Hence, ethnobiological information and practice within any customs have been reported to vary by factors such as geographical basis, traditions, belief, livelihood, educational background, social status and relations, income class, age, and gender [58, 59, 60]. The flow of knowledge from seniors to children and its enrichment subsequently is directly conveyed through observation, imitation, free flow of information among community members, history telling, and myths [61].
The main system of traditional knowledge transfer on types of medicinal plants, traditional concepts of disease, and ways of diagnosis among traditional healers in Suro Barguda District was through word of mouth (no written documents obtained), with maximum secrecy following mainly the selected male line of the family. The way they are sharing their indigenous knowledge with their descendants was also found to be similar. This may cause indigenous knowledge to be threatened shortly unless certain measures are taken which was also clearly seen in other parts of the country and abroad [34, 44, 50, 53, 54, 55, 56].
Traditional knowledge is built with years of experience so elders were more knowledgeable in traditional medicines than youngsters in the study area. The depth and width of traditional knowledge on medicinal plants become lesser and lesser due to its secrecy, the unwillingness of the young generation to gain the knowledge, influence of modern education which all result in its gradual disappearance. Ethnomedicinal knowledge diminishes with the death of elderly knowledgeable members of the society since fewer and fewer young people are willing to acquire this knowledge. That is why [62] said that erosion of knowledge on medicinal plants is more significant in species collected from forests for use in treating rare and unusual ailments. This finding was in line with the reports of [63, 64, 65].
Conservation practices
Dwellers of Suro Barguda District and their livestock population depend mainly on the natural resources of the area for their existence. Deforestation for timber production or construction, overgrazing, charcoal production, and fuelwood collection was claimed to be the anthropogenic causes of resource depletion. This finding was in line with the reports of [46, 66]. Highly affected dry evergreen montane forest and the remaining woodland area were severely degraded due to overgrazing with immense livestock population and illegal charcoal production and fuelwood collection. Not only medicinal plant species were affected but also the vegetation as a whole was in a critical condition. Some conservation practices were implemented in a very specific area of the district but this did not guarantee the wellbeing of plant diversity and their contribution to the perpetuation of life in the area (no pronounced conservation effort).
Inhabitants of the study area simply went to the forest, woodland, or grazing area to collect medicinal plants as their need arose and did not worry about the long-term survival of these plants. Most of these informants gave the reason that the medicinal plants were easily accessible in their surroundings and hence no need for personal effort to conserve these plants. Because of this many plants in the study area were highly threatened with anthropogenic and natural factors. The natural factor affecting medicinal plant species was irregular and very short rainy season, prolonged and recurrent drought. Hence, sustainable land management which involves both the conservation and improvement of the present vegetation cover, such as through enrichment planting, enhancing soil fertility, and rehabilitating degraded lands is required to reduce pressure on and destructive use of the natural resources. This could be achieved by solving the problems associated with open access to forest resources through sustainable forest management involving the local communities neighboring this vegetation as co-managers and co-beneficiaries of the generated revenues.
Conclusion
Most of the ethnoveterinary medicinal plants of the study area were found to play a multipurpose role across different use categories and consequently, some are under serious pressure challenging their survival. Hence, recorded high use value indices of multipurpose plant species in the study area can be used as signals of high use pressure and can be used as keys to design and implement well-coordinated complementary in situ and ex situ conservation activity to save these widely used plant species. These findings were in agreement with the third hypothesis of the research "the local people are equipped with unique indigenous knowledge and culture in using ethnoveterinary medicinal plants for different purposes." Findings of this study indicated that there was higher usage of leaves of most medicinal plants to prepare various traditional remedies. Even though collecting these parts seems not harming much the regular physiological activities of the plant, those plants only with a limited number of leaves can be endangered unless proper consideration is given. Hence, conservation work in the area needs to give prior attention to protect such types of plant species. Traditional practitioners diagnose their diseased livestock through observation and asking the owner of the animal about the signs of the disease and then prepare the medicine to administer it accordingly based on their cultural knowledge on symptoms, corresponding illnesses, and therapeutic medicinal species held in the knowledge of indigenous people. This may be more effective if these people obtain certain training from modern health professionals about how to identify some diseases based on their symptoms especially those which are easily communicable to minimize the possible severe problems that could happen on the local livestock and how to determine the doses of the preparations.
Traditional practitioners in the district also showed varying degrees of traditional medicinal plant use knowledge based on differences in age, experience, gender, and education level. More ethnomedicinal knowledge was observed in elderly members of the community than in younger groups; experienced/key practitioners than the general public; and more with the illiterate than the literate. Because of the cultural norm and secrecy of the traditional medication system, this knowledge is transmitted along the selected male line of the family members due to which males could be more knowledgeable than females even if the difference in knowledge concerning gender was not exaggerated in the study area. Oral transmission of traditional knowledge and its flow only through the selected male line of the family for its secrecy may cause it to be depleted shortly concerning modernization and ignorance of the new generation. High ICF, FL, and medicinal use values testing exercises result showed that the selected medicinal plants of Suro Barguda District have promising bioactivity elements. These findings were in line with the fourth hypothesis "the traditional herbalists in the community are knowledgeable about healing plants, their preparation, and applications."
Recommendations
Plants afford a great economic and social value for the rural communities living as semi- pastoralists being used as forage and medicine for their livestock, source of both timber and other non-timber products as well as regulators of climatic conditions. Therefore, to ease the present human influence on the natural vegetation and for its future management on a sustainable basis in the district, the following recommendations are forwarded:
- Raising public awareness, through extension programs, on the multiple uses of plant resources to safeguard the plant diversity;
- Conservation action should be followed with close follow up about its sustainability not to be affected by resources used for different needs;
- In natural resource conservation such as regional or national protected areas, giving responsibility and sense of ownership to the local community so that they assume it as their property and they will manage and conserve it to become beneficiaries of the economic payback that can be obtained from this action;
- Conservationists should set up medicinal plant nursery sites in co-operation with the District's Agriculture and Rural Development Office to propagate seedlings of the most-preferred medicinal plants, followed by a parallel distribution of seedlings to the local community as a possible means of reducing pressure on natural stands and conserve useful medicinal plant species;
- The indigenous knowledge of pastoralists about plants (a traditional system of rangeland management) and livestock (breeding different species of livestock (grazers with browsers), as well as their environmental management system (traditional forest, soil and water conservation system), should be incorporated in the planning and implementation of developmental interventions;
- Carefully designed community-based and participatory approaches are recommended to control bush encroachment through minimizing deforestation, overgrazing, and raising awareness of the local community to use controlled burning by clearing unwanted bushes;
- Medicinal plants such as Prunus africana and Syzygium guineens should be given conservation priority for their multipurpose uses;
- Conservation measures which might be designed for vegetation resources of Suro Barguda District by policymakers, natural resource managers or stakeholders would need to take into account special protection and monitoring of the endemic taxa as well as the most important useful plant species found in the vegetation;
- Good effort should be made by stakeholders to close the observed generation gap in indigenous knowledge (b/n elders and youngsters) through uninterrupted professional support and training of local communities to preserve their traditional knowledge and practices through systematic documentation;
- The efficacy of the preparations, techniques, and practices need to be investigated to identify promising plants for use in livestock development plans. So, bioactive chemicals of Croton macrostachyus and Teclea salicifolia should be screened out in scientific works for their pharmacological potentials because they were used to treat different livestock diseases (about six diseases each).